Cycloidal ship propeller



June 28, 1966 K. BLICKLE ETAL CYCLOIDAL SHIP PROPELLER Original FiledNov. 14, 1962 INVENTOR5 Karl Buckle Eugen H6Hich WiLhelrn Hub UnitedStates Patent Original application Nov. 14, 1962, Ser. No. 239,866.Divided and this application Apr. '7, 1965, Ser. No.

7 Claims. ((31. 170-151 The present application is a divisional of. ourcopending application, Serial No. 239,866, filed November 14, 1962, andentitled Cycloidal Ship Propeller.

This invention relates to cycloidal propellers, particularly for ships,which have a blade wheel body adapted to be rotatably supported andcarrying a plurality of blades extending substantially parallel to theaxis of rotation of the body while being pivotally mounted on the body.These blades are uniformly circumferentially distributed on the bodyalong a blade circle which is coaxial with the axis of rotation of thebody.

With propellers of the cycloidal type, the blades are tilted about acentral axis thereof conforming to the axis of rotatable support of theblades to change the ange of attack of the blades, thereby to obtainpropulsion in a direction at right angles to the axis of rotation of theblade wheel body. The individual blades of the propeller are connectedthrough a blade actuating linkage system, a socalled kinematic, whichincludes a central control disc common to all of the blades and which isoperable from outside the blade body for adjusting the linkage.

The linkage system includes at least one lever fixed to the respectiveblade, which may be termed a blade lever, and also includes a connectingrod linked to the blade lever and, furthermore, includes a crank leverpivotally connected in the region of the junction of the arms thereof tothe blade wheel body with one end of one arm of the crank lever beingconnected to the connecting rod while the end of the other arm of thelever is connected to the control disc.

With many ships employing cycloidal propellers, two propellers arerequired to obtain the propulsive effort desired and, when the ship ison a straight course, it is desirable to compensate for the respectivetorques of the two propellers by causing them to rotate in respectivelyopposite directions.

With known cycloidal propeller blade actuating linkage systems as setforth, for example, in United States 2,250,- 772 or 2,291,062, thedrawback is encountered that, with propellers rotating in respectivelyopposite directions, the blade wheel body and the blade actuatinglinkage system has to be designed differently for propellers rotating inclockwise direction than for propellers rotating in counterclockwisedirection. This in turn means that for producing clockwise rotatingpropellers, machine shop drawings, models, devices and similarmanufacturing aids have to be produced other than what is necessary forcounterclockwise rotating propellers so that the cost for themanufacture and the stockkeeping of the propellers is considerablyincreased.

It is, therefore, an object of the present invention to provide acycloidal ship propeller, which will overcome the above mentioneddrawbacks.

. It is another object of this invention to provide a cycloidal shippropeller and in particular the blade actuating linkage system in such away that the same type of blade wheel body may be employed forpropellers rotating in clockwise direction and for propellers rotatingin counter-clockwise direction.

These and other objects and advantages of the invention will appear moreclearly from the following specifi- 3,258,074 Fatented June 28, 1966cation in connection with the accompanying drawings, in which:

FIGURES 1, 2 and 3 diagrammatically illustrate three embodiments of acycloidal ship propeller with a blade actuating linkage system accordingto the present invention;

FIGURE 4 is a view showing the propeller of FIGURE 1 with the controldisc shifted oil center; and

FIGURE 5 is a section taken on line V-V of FIGURE 4 showing in moredetail the construction of a slide block forming a part of the slidelinkage system.

General arrangement In order to overcome the drawbacks outlined abovewith heretofore known linkage systems for cycloidal ship propellers,according to the present invention, the axis of the pivot by means ofwhich the crank lever of the blade actuating linkage system is linked tothe blade wheel body is arranged in a radial plane defined by the axisof rotation of the blade wheel body and the pivot axis of the respectiveblade actuated by said blade actuating linkage system.

A blade actuating linkage system designed in this way makes it possibleto produce one and the same type blade wheel body for propellersrotating in clockwise direction as well as for propellers rotating incounter-clockwise direction. Thus, instead of providing two blade wheelbodies as was heretofore necessary, when employing a blade wheel linkagesystem according to the invention, only one type of blade wheel body isnecessary so that the costs for keeping stock and replacement parts willbe greatly reduced and the replacement of the parts Will be greatlysimplified.

Structural arrangement Referring now to the drawings in detail, itshould be noted that, in FIGURES l, 2 or 3, the blades are illustratedin their middle position, i.e., in a position in which the blade istangential to the circle which has its center located on the pivot axisof said blade.

As will be seen from the figures in the drawings in which the sameelements have been designated with the same reference numerals, withinthe blade Wheel body 1 of the cycloidal propeller, which blade wheelbody is rotatably journalled in the ship body, there is provided acontrol disc 3 common to all of the blades 2 and operable from theoutside of the blade wheel body. In addition thereto, within saidrotatable blade wheel body 1 there is provided a number of bladeactuating linkage systems corresponding to the number of the blades withwhich the blade wheel body is equipped. For purposes of clarity,however, each of the various FIGURES 1 to 3 illustrates one blade wheelactuating linkage system only whereas FIGURE 4 shows the cycloidalpropeller according to FIGURE 1 with four blades A, B, C, D and all thefour actuating linkage systems pertaining thereto.

As will be seen from the FIGURES 1-4, each blade actuating linkagesystem has a cross head 4 pivotally journalled in control disc 3, andalso comprises a crank lever 7 which on one end is slidably journalledin cross head 4 and on the other end is pivotally connected to aconnecting rod 5 and is furthermore by means of a pivot 6 pivotallyconnected to the blade wheel body 1. Each blade actuating linkage systemfurthermore comprises a blade lever 8. The axis of the pivot 6 mountedon the blade wheel body 1 is located in the radial plane 10 defined bythe axis of rotation 11 of the blade wheel body 1 and the pivot axis 12of the respective blade 2 pertaining thereto.

It will be appreciated that if control disc 3 has been moved out of itscentral position for instance by a control stick connected to the centerof the control disc, 21

controlled oscillating movement about the middle position of blades 2will be imparted upon said blades through the intervention of thecontrol disc 3. In the middle position, the profile chord 13 is tangentto the blade circle 9.

A favorable design of the blade actuating linkage system is illustratedin FIGURE 1. This design obtains a favorable adjustment of the bladeangle between the profile chord 13 of blades 2 and the tangent to theblade wheel circle 9 and, thereby, obtains a favorable course of theso-called blade angle curve and, thus, a high degree of efficiency ofthe propeller. Furthermore, better lubrication of the individual jointsof the blade actuating system is obtained.

More specifically, crank lever 7 is so constructed that when the bladesoccupy their tangential positions as shown in FIGURE 1, that arm of thecrank which is connected to control disc 3 forms an angle ofapproximately 10 degrees with radial plane 10, while both arms of cranklever 7 are located on one and the same side of the said radial plane10.

Expressed generally, according to one embodiment of the presentinvention, the blade actuating linkage system is so designed that in themiddle position of the respective blade, the lever arm connected to thecontrol disc and pertaining to the crank lever, confines with the radialplane an angle of 10 while the lever arms of the crank lever are locatedon one and the same side of the radial plane.

According to a further development of the invention, the blade actuatinglinkage system is so designed that the lever arms of the crank leverconfine with each other an angle of 100 while the said lever arms arelocated on one and the same side of the radial plane. Such anarrangement is shown in FIGURE 2 according to which the two lever armsof crank lever 7 confine with each other an angle of 100", while thatlever arm of two arm lever 7 which is connected to the control disc 3will be located in the radial plane 10 when the blade 2 occupies itstangential position.

The arrangement shown in FIGURE 3 differs slightly from that of FIGURES1 and 2 inasmuch as according to FIGURE 3 the angle confined by the twolever arms of crank lever 7 amounts to 100, whereas that lever arm whichis connected to control disc 3 is in tangential position of blade 2inclined with regard to the radial plane 10 by an angle of 10. Also inthis instance the two lever arms of the crank lever 7 are located on oneand the same side of said radial plane 10.

By appropriately selecting the angles between the lever arm pertainingto the crank lever and connected to said control disc and said radialplane and the angle of the lever arms of the crank lever, it will bepossible to adjust the blade pitch to more favorable values than waspossible with heretofore known designs of blade actuating linkagesystems, so that with the present invention better degrees of efiiciencyof the propeller can be obtained than were heretofore possible.

Furthermore, by an appropriate design of the blade actuating linkagesystem according to the present invention, there will be obtained theadvantage that with the control center in a position out of its centralposition the torques acting on the control disc and varying severaltimes from positive to negative peaks during a rotation of thepropeller, will have approximately the same magnitude. Consequently, thepeaks of the reciprocating forces in the individual joints of thekinematics will be reduced while simultaneouly a more favorablelubrication will be obtained than was heretofore obtainable.

In FIGURE 4 a cyloidal propeller is shown With the cotnrol disc 3shifted otf center so that the position of the four propeller blades A,B, C and D in the four quadrants will be seen.

The center point 11 of the control disc 3 is displaced on the transversediameter 10 from the center point of the blade wheel body 1 by adistance e towards the left. This displacement corresponds to adirection of attack of the force of the water on the propeller andthereby a direction of advancement of the propeller and of the ship inupward direction (with regard to the draw ing), as shown in FIGURE 4 byarrow p.

In both positions A, C of the propeller blade 2 in which the pivot axis12 of the blade coincides with the point of intersection of thetransverse diameter 10 with the blade wheel orbit 9, the blade istangential to the blade wheel orbit as was the case before.

In the two other positions B, D which correspond to an advancingmovement of the blade on the bladewheel orbit by or 270 respectivelywith respect to the blade position A the blades are tilted out of thetangential position, in such a way that the head of the blade at the topof the view is tilted outwardly, and at the bottom of the view the headof the blade is tilted toward the inside. That blade which is designatedA is after a rotation of the wheel body in the direction of the arrow qof 90 in the position of the blade B, after a further rotation of 90(180 counting from the starting position) it has reached the position ofthe blade C, namely, again a tangential position, and finally, after afurther rotation of 90 (270 from the starting position) it has reachedthe position of the blade D.

With regard to the slide block element of cross head 4, as will be seenin FIGURE 5, this element slidably rcceives the pertaining arm of thecrank lever 7 and is pivotally connected by pivot pin 4a with thecontrol disc 3 for free pivotal movement thereon.

The problem of designing a blade wheel body and blade actuating linkagesystem for cycloidal propellers which can be employed for both clockwiserotating propellers and counter-clockwise propellers is by no means assimple as by merely pivoting the linkage to the blade wheel body on aline passing through the center of rotation of the blade wheel body andthe pivot axis of the respective blade. Many attempts have been made tofind such a linkage but heretofore such linkage systems have beendefective in providing that the propeller will operate efficiently andsubstantially free of cavitation.

Freedom of the propeller from cavitation is extremely important,inasmuch as the reliability and safety of the propeller depend largelyupon this feature. The propeller at the same time must have a highdegree of efficiency throughout the useful range of pitch thereof.

The structure disclosed in the present invention solves this problemsatisfactorily for the first time and provides a suitable propellerconstruction which provides for efficient cavitation-free operation ofpropeller while one and the same blade wheel body can be employed forboth clockwise rotating and counter-clockwise rotating propellers. Theblades can, of course, be reversed on the propeller body when thedirection of rotation of the propeller body is reversed and by formingthe linkage connecting the control plate with the blade levers of fiatmembers, such as from stamped sheet metals parts or flat cast, or forgedmembers, the linkage members themselves can also be employed forpropellers of both senses of rotation.

It will be evident that the provision of a suitable blade actuatinglinkage system and a suitable blade wheel body in accordance with theprinciples of the present invention greatly reduces the cost ofmanufacture of the propellers and reduces the inventory of parts and thelike.

It will be understood that this invention is susceptible to modificationin order to adapt it to different usages and conditions; andaccordingly, it is desired to comprehend such modifications within thisinvention as may fall Within the scope of the appended claims.

What is claimed is:

1. A cycloidal ship propeller comprising: a blade wheel body rotatableon a central axis, a plurality of blades arranged along a circleconcentric with said blade wheel central axis and in substantiallyuniformly spaced relationship to each other, pivot means pivotallysupporting said blades on said blade wheel body, each pivot meansdefining'a pivot axis for its respective blade, said pivot axes beingsubstantially parallel to each other and to said central axis, each ofsaid blades being capable of an oscillating movement about its pivotaxis and about a middle position of the blade in which the respectiveblade is tangential to the circle along which the pivot axes of saidblades are arranged, adjustable control means common to all of saidblades and movable selectively from a central position coaxial with saidcentral axis of said blade wheel body into any one of a plurality ofpositions eccentric with regard to said central axis of said blade wheelbody and vice versa to govern the oscillating movement of said blades, aplurality of blade actuating linkage systems respectively operativelyconnecting said adjustable control means with said pivot means so thateach of said blades will be operable in response to a rotation of saidwheel body and while said adjustable control means occupies any of itspossible positions to carry out an oscillating movement having thepredetermined magnitude of the blade angles which correspond to therespective circular positions of the pivot axes of the blades duringtheir circular movement with said blade wheel body, each of said bladeactuating linkage systems comprising at least one lever operativelyconnected to the respective blade pivot means and also comprising aconnecting rod linked to said lever, each of said blade actuatinglinkage systems furthermore comprising a crank lever having one of itsarms connected to said connecting rod and having its other armoperatively linked to said adjustable control means, the means linkingthe said other arm of each crank lever to said control means comprisinga member tiltably mounted on said adjustable control means and slidablyengaging said other arm of said crank lever, means pivotally connectingthe crank lever in the region of the junction of the two arms thereof toa point on the blade wheel body, said point on the blade wheel bodybeing located in a radial plane passing through the axis of rotation ofsaid blade wheel body and through the axis of the pivotal connection ofthe respective blade with said blade wheel body said point on the bladewheel body being located between said areas, said other arm of saidcrank lever forming with said radial plane an angle of approximately 10,the arrangement being such that for each blade and the bladeadjustinglinkage system pertaining thereto, in the central position of saidcontrol means, with regard to the direction of rotation of said wheelbody,'said lever and said rod and at least that arm of the crank leverwhich is linked to said rod, all pertaining to said blade actuatinglinkage system, are located behind said radial plane.

2. A cycloidal ship propeller comprising: a blade wheel body rotatableon a central axis, a plurality of blades arranged along a circleconcentric with said blade Wheel central axis and in substantiallyuniformly spaced relationship to each other, pivot means pivotallysupporting said blades on said blade wheel body, each pivot meansdefining a pivot axis for its respective blade, said pivot axes beingsubstantially parallel to each other and to said central axis, each ofsaid blades being capable of an oscillating movement about its pivotaxis and about a middle position of the blade in which the respectiveblade is tangential to the circle along which the pivot axes of saidblades are arranged, adjustable control means common to all of saidblades and movable selectively from a central position coaxial with saidcentral axis of said blade wheel body into any one of a plurality ofpositions eccentric with regard to said central axis of said blade wheelbody and vice versa to govern the oscillating movement of said blades, aplurality of blade actuating linkage systems respectively operativelyconnecting said adjustable control means with said blade pivot means sothat each of said blades will be operable in response to a rotation ofsaid wheel body and while said adjustable control means occupies any ofits possible positions to carry out an oscillating movement having thepredetermined magnitude of the blade angles which correspond to therespective circular positions of the pivot axes of the blades duringtheir circular movement with said blade wheel body, each of said bladeactuating linkage systems comprising at least one lever operativelyconnected to the respective blade pivot means and also comprising aconnecting rod linked to said lever, each of said blade actuatinglinkage systems furthermore comprising a twoarm crank lever having oneof its arms connected to said connecting rod and having its other armoperatively linked to said adjustable control means, the means linkingthe said other arm of each crank lever to said control means comprisinga member tiltably mounted on said adjustable control means and slidablyengaging said other arm of said crank lever, said one arm together withsaid other arm forming an angle of approximately means pivotallyconnecting the crank lever in the region of the junction of the two armsthereof to a point on the blade wheel body, said point on the bladewheel body being located in a radial plane passing through the axis ofrotation of said blade wheel body and through the axis of the pivotalconnection of the respective blade with said blade wheel body and alsobeing located between said axes, the arrangement being such that foreach blade and the blade adjusting linkage system pertaining thereto, inthe central position of said control means, with regard to the directionof rotation of said wheel body, said lever and said rod and also atleast that arm of the crank lever which is linked to said rod, allpertaining to said blade actuating linkage systems, are located behindsaid radial plane.

3. A cycloidal ship propeller comprising; a blade wheel body, aplurality of blades pivotally supported by said blade wheel body andhaving their pivot axes arranged along a circle in substantiallyuniformly spaced relationship to each other, said pivot axes beingsubstantially parallel to each other, each of said blades being capableof an oscillating movement about its pivot, adjustable control meanscommon to all of said blades and movable selectively from a centralposition coaxial with said blade Wheel body into any one of a pluralityof positions eccentric with regard to said blade wheel body and viceversa to govern the oscillating movement of said blades, each of saidblades comprising a pivot and being oscil- 'latable about a middleposition thereof in which the respective blade is tangential to thecircle along which the pivot axes of said blade ar arranged, a pluralityof blade actuating linkage systems respectively operatively connectingsaid adjustable control means with said blades, each of said bladeactuating linkage systems comprising at least one lever operativelyconnected to the respective blade pivot and also comprising a connectingrod linked to said lever, each of said blade actuating linkage systemsfurthermore comprising a two-arm lever pivotally connected to said bladewheel body and having one of its arms connected to said connecting rodand having its other arm connected to said adjustable control means, thearrangement being such that for each blade and the linkage systempertaining thereto the axis of the pivotal connection of the two-armlever of the respective linkage system with said blade wheel body islocated in the radial plane which passes through the axis of rotation ofsaid blade Wheel body and through the axis of the pivotal connection ofthe respective blade with said blade wheel body, and in which middleposition of the respective blade that lever arm of said two-arm leverwhich is connected to said adjustable control means forms with saidradial plane an angle of about 10 degrees, the lever arms of saidtwo-arm lever in said middle position of the respective blade beinglocated at one and the same side of said radial plane.

4. A cycloidal ship propeller according to claim 3, in

which each of said blades oscillates about a middle position in which thblade is tangential to the circle along which the pivot axes of saidblades are arranged, and in which the lever arms of said two-arm leverconfine with each other an angle of about 90 to 100 degrees, the leverarms of said two-arm lever in said middle position of the respectiveblade being located at one and the same side of said radial plane.

5. A cycloidal ship propeller comprising; a blade wheel body rotatableon a central axis, a plurality of blades pivotally supported by saidblade wheel body and having their pivot axes arranged along a circleconcentric with said blade wheel central axis and in substantiallyuniformly spaced relationship to each other, said pivot axes beingsubstantially parallel to each other and to said central axis,adjustable control means common to all of said blades and movableselectively from a central position coaxial with said central axis ofsaid blade wheel body into any one of a plurality of positions eccentricwith regard to said central axis of said blade wheel body and vic versato govern the oscillating movement of said blades, each of said bladescomprising a pivot and being oscillatable about a middle position of theblade in which the respective blade is tangential to the circle alongwhich the pivot axes of said blades are arranged, a blade actuatinglinkage system operatively connecting said adjustable control means witheach said blade and comprising at least one lever operatively connectedto the respective blade pivot and also comprising a connecting rodlinked to said lever, each said blade actuating linkage systemfurthermore comprising a two-arm lever having the outer one of its armsconnected to said connecting rod and have the outer end of its other armoperatively linked to said adjustable control means, means pivotallyconnecting the two-arm lever in the region of the junction of the twoarms thereof to a point on the blade wheel body which is located in aradial plane passing through the said central axis of said wheel bodyand through the axis of the pivotal connection of the respective bladewith said blade wheel body and also being located between said axes, thesaid one lever and rod and at least that arm of the two-arm lever whichis linked to said rod, all pertaining to said blade actuating linkagesystem, in the central position of said control means, being locatedbehind said radial plane with respect to the direction of rotation ofsaid body.

6. A cyclodial ship propeller according to claim 5, in which eachtwo-arm lever forms an angle and the means linking the said other arm ofeach two arm-lever to said control means comprises a member tiltablymounted on said adjustable control means and slidably engaging saidother arm of said two-arm lever, said last mentioned arm forming withsaid radial plane an angle of approximately 10.

7. A cycloidal ship propeller according to claim 5, in which eachtwo-arm lever forms an angle and the means linking the said other arm ofeach two-arm lever to said control means comprises a member tiltablymounted on said adjustable control means and slidably engaging saidother arm of said two-arm lever, said one arm together with its otherarm forming an angle of approximately 100".

References Cited by the Examiner UNITED STATES PATENTS 2,250,772 7/1941Mueller et al. 170148 2,859,829 11/1958 Mueller 170-147 FOREIGN PATENTS114,323 9/1929 Austria. 285,911 10/ 1928 Great Britain. 721,374 1/1955Great Britain.

SAMUEL LEVINE, Primary Examiner.

E. A. POWELL, JR., Assistant Examiner.

1. A CYCLOIDAL SHIP PROPELLER COMPRISING: A BLADE WHEEL BODY ROTATABLE ON A CENTRAL AXIS, A PLURALITY OF BLADES ARRANGED ALONG A CIRCLE CONCENTRIC WITH SAID BLADE WHEEL CENTRAL AXIS AND IN SUBSTANTIALLY UNIFORMLY SPACED RELATIONSHIP TO EACH OTHER, PIVOT MEAN PIVOTALLY SUPPORTING SAID BLADES ON SAID BLADE WHEEL BODY, EACH PIVOT MEANS DEFINING A PIVOT AXIS FOR ITS RESPECTIVE BLADE, SAID PIVOT AXES BEING SUBSTANTIALLY PARALLEL TO EACH OTHER AND TO SAID CENTRAL AXIS, EACH OF SAID BLADE BEING CAPABLE OF AN OSCILLATING MOVEMENT ABOUT ITS PIVOT AXIS AND ABOUT A MIDDLE POSITION OF THE BLADE IN WHICH THE RESPECTIVE BLADE IS TANGENTIAL TO THE CIRCLE ALONG WHICH THE PIVOT AXES OF SAID BLADES ARE ARRANGED, ADJUSTABLE CONTROL MEANS COMMON TO ALL OF SAID BLADES AND MOVABLE SELECTIVELY FROM A CENTRAL POSITION COAXIAL WITH SAID CENTRAL AXIS OF SAID BLADE WHEEL BODY INTO ANY ONE OF A PLURALITY OF POSITIONS ECCENTRIC WITH REGARD TO SAID CENTRAL AXIS OF SAID BLADE WHEEL BODY AND VICE VERSA TO GOVERN THE OSCILLATING MOVEMENT OF SAID BLADES, A PLURALITY OF BLADE ACTUATING LINKAGE SYSTEMS RESPECTIVELY OPERATIVELY CONNECTING SAID ADJUSTABLE CONTROL MEANS WITH SAID PIVOT MEANS SO THAT EACH OF SAID BLADES WILL BE OPERABLE IN RESPONSE TO A ROTATION OF SAID WHEEL BODY AND WHILE SAID ADJUSTABLE CONTROL MEANS OCCUPIES ANY OF ITS POSSIBLE POSITIONS TO CARRY OUT ON OSCILLATING MOVEMENT HAVING THE PREDETERMINED MAGNITUDE OF THE BLADE ANGLES WHICH CORRESPOND TO THE RESPECTIVE CIRCULAR POSITIONS OF THE PIVOT AXES OF THE BLADES DURING THEIR CIRCULAR MOVEMENT WITH SAID BLADE WHEEL BODY, EACH OF SAID BLADE ACTUATING LINKAGE SYSTEM COMPRISING AT LEAST ONE LEVER OPERATIVELY CONNECTED TO THE RESPECTIVE BLADE PIVOT MEANS AND ALSO COMPRISING A CONNECTING ROD LINKED TO SAID LEVER, EACH OF SAID BLADE ACTUATING LINKAGE SYSTEMS FURTHERMORE COMPRISING A CRANK LEVER HAVING ONE OF ITS ARMS CONNECTED TO SAID CONNECTING ROD AND HAVING ITS OTHER ARM OPERATIVELY LINKED TO SAID ADJUSTABLE CONTROL MEANS, THE MEANS LINKING THE SAID OTHER ARM OF EACH CRANK LEVER TO SAID CONTROL MEANS COMPRISING A MAMBER TILTABLY MOUNTED ON SAID ADJUSTABLE CONTROL MEANS AND SLIDABLY ENGAGING SAID OTHER ARM OF SAID CRANK LEVER, MEANS PIVOTALLY CONNECTING THE CRANK LEVER IN THE REGION OF THE JUNCTION OF THE TWO ARMS THEREOF TO A POINT ON THE BLADE WHEEL BODY, SAID POINT ON THE BLADE WHEEL BODY BEING LOCATED IN A RADIAL PLANE PASSING THROUGH THE AXIS OF ROTATION OF SAID BLADE WHEEL BODY AND THROUGH THE AXIS OF THE PIVOTAL CONNECTION OF THE RESPECTIVE BLADE WITH SAID BLADE WHEEL BODY SAID POINT ON THE BLADE WHEEL BODY BEING LOCATED BETWEEN SAID AREAS, SAID OTHER ARM OF SAID CRANK LEVER FORMING WITH SAID RADIAL PLANE AN ANGLE OF APPROXIMATELY 10*, THE ARRANGEMENT BEING SUCH THAT FOR EACH BLADE AND THE BLADE ADJUSTING LINKAGE SYSTEM PERTAINING THERETO, IN THE CENTRAL POSITION OF SAID CONTROL MEANS, WITH REGARD TO THE DIRECTION OF ROTATION OF SAID WHEEL BODY, SAID LEVER AND SAID ROD AND AT LEAST THAT ARM OF THE CRANK LEVER WHICH IS LINKED TO SAID ROD, ALL PERTAINING TO SAID BLADE ACTUATING LINKAGE SYSTEM, ARE LOCATED BEHIND SAID RADIAL PLANE. 